According to DNSreports.com, "[ERROR: The parent servers say that the domain marshmellowsurprise.com does not exist. Note that the DNSreport only works on domains, not hostnames.]".
I'd contact support, but I'd also try "editing" the "fully hosted" domain and "re-saving" it (make no actual edits, just open the dialog page and submit the form again). Often, this can solve the problem by regenerating the necessary DNS entries.